Flotation method



Patented June 9, 1942 UNITED STATES PATENT OFFICE FLOTATION METHOD Hugh W. Coke, Juneau, Territory of Alaska No Drawing. Application July 24, 1940,

- Serial No. 347,274

13 Claims.

in that they assist in producing a better froth and eifectthe collection of the desired mineral values present in the ore in cooperation with other frothing and collecting agents, if the metallurgy of the particular ore under treatment makes the use of additional collectingor frothing agents advisable. The new reagents are useful in the beneflciation of ores, particularly metalliferous ores, such as copper, lead, zinc, silver, gold, and tungsten; and also nonmetallic ores, for example, talc. They are useful in the beneflciation of oxidized metalliferous ores as well as sulphide metalliferous ores.

The use of sulphonated soaps of alkali metals produced by saponifying a sulphonated fatty acid with sodium hydroxide, and the corresponding soaps of heavy metals, such as lead and copper, produced by reaction between the alkali soap and a heavy metal salt, such as lead acetate or copper acetate, as flotation reagents forv the concentration of metalliferous ores and of ores of so-called non-metallic minerals, is now known. However, I have found that organo-metallic compounds-or mixtures thereof can be rendered much more effective as flotation reagents if they,

' and will not give as high recoveries of the desired mineral values aswhen the reagent is prepared by neutralization of the sulphonated castor oil with an alkali or an alkaline earth metal carbonate, Reagents formed by saponifying sulphonated castor oil with an alkali or alkaline earthmetal hydroxide, regardless of the amount of alkali metal hydroxide used, produces a heavy, matted froth as distinguished from a relatively 10 strong not-too-heavily mineralized froth in which the bubbles are of the desired size, such as is produced by the product resulting from the neutralization of the sulphonated castor oil with an alkali metal or an alkaline earth metal 15 carbonate. However, in order to obtain the ad-" vantages resulting from the present invention, the castor oil must first have been sulphonated, as satisfactory results have not been obtained with-a product resulting from the treatment of raw castor oil, either with an alkali metal or an alkaline earth metal carbonate.

Accordingly, the present invention relates to a flotation reagent which is the product, a derivative thereof, or a mixture of the products resulting from the neutralization of sulphonated castor oil with an alkali metal or an alkaline earth metal carbonate, and to a froth flotation method of concentrating minerals from their ores with such a product or mixtureof products.

or the products from whiqhjllg are derived, are 0 While under certain conditions ammonium carproduced by neutralization of sulphonated castor oil (the alkali salt of ricinoleo-sulphuric acid) wit hgn alkali or an alkaline earth metal carbonatejinsteadofmapomflcation of the sulused, I prefer to use an alkali metal or an alkaline earthmetal to neutralize the sulphonated castor oil, as the product resulting from neutralization of the oil with amphonated a t r oi with an alkal or alkaline monium carbonate is relatively unstable and earth metal hydroxide. An organo-metallic compound when so prepared is effective when the milling is carried out both in soft water and hard water. It offers increased advantages when the milling is conducted in hard wvatenj dium carb natenas the .alkalmeieutrahzing agent is preferred, and in the further description of the invention reference will be made to soand results have been attained with such a recarbonate as the if ent.

agent when milling in sea water which heretofore it has been impossible to attain when using the usual frothers and collecting agents.

The flotationreagent of the present invention is prepared by the neutralization of castor oilwhich has been sulphonated by reaction with If sodium hydroxide, for example, is caused any a p opr a e sulp ona ns a ent or in any tion of minerals, possesses much less selectivity well known manner, with sodium carbonate. When a reaction product of a heavy metal is desired, the product resulting from the neutralization of the sulphonated castor oil with the alkali metal carbonate, may be caused to react vention was prepared by dissolving 75 parts by with a salt of a heavy metal, such as lead acetate or copper acetate, whereupon the metal atom covery of that difficult fraction, and the benefit of the frothing properties of the alkali metal of the heavy metal salt will be substituted in the product. The relative extent of collection and neutralization product in place of the alkali metflocculation, and frothing, produced by the rea1. Salts of various heavy metals, such as lead, 5 agent will depend upon the amount of the heavy iron, zinc, manganese, cobalt and copper, may be used to form the heavy metal product, as the resulting product of all of them shows characteristic powerful flocculation of slimed minerals, but ordinarily a lead salt is preferred.

Ordinarily a mixture of the product resultin from the neutralization of sulphonated castor oil with sodium carbonate and the heavy metal product derived therefrom will be used. The alkali metal or alkaline earth metal product of the neutralization, supplemented by a small amount of pine oil or cresylic acid, forms an excellent frothing agent, while the heavy metal product derived therefrom is a powerful collecting and flocculating agent. However, either product may be used without the other. 1

In one example, the reagent of the present inconsequently upon the relative amounts of the heavy metal product and alkali metal products present.

The alkali metal product prepared in the manner set forth and the heavy metal product derived therefrom' will function as collecting and fiocculating, and frothing agents, respectively, with all types of ores and they have been found to be particularly useful with ores producing a high slime content when pulped, such as ores containing sericite and chlorite, which when pulped produce colloidal slimes.

In the concentration of certain ores,'t'h'e heavy metal product as prepared above may be the only flocculating and collecting agent used, but with most ores it will be found desirable to use ard collecting agents, such as the xanthates and the Aerofloats. However, when the heavy metal product is used, such additional collecting agents may be used in lesser amounts. Also, in froth flotation it is desirable" to use the usual frothing agents along with the alkali metal product as it ordinarily has insufficient frothing power when used alone, but when used with proper proportions of standard frothing agents,

weight of sodium carbonate in 1000 parts of water, after which 50 parts of sulphonated castor oil was added slowly, with stirring, to the solution of sodium carbonate. The resulting product was the sodium neutralized ricinoleo-sulphuric acid.

In another example, 400' grams of lead acetate in solution was added to 20 lbs. of a solution of the neutralized product prepared as set forth above to form the lead salt of the neutralized ricinoleo-sulphuric acid.

In preparing the alkali metal product in the manner set forth, it is preferred to use an amount of alkali carbonate sufficient to neutralize substantially all of thesulphonated castor oil. Ordinarily, the amount of the alkali carbonate will be between 1.1 and 2 times. the amount of sulphonated castor oil. The amount of water may be varied but the amount given above, as well as the relative amounts of sulphonated castor oil and alkali metal carbonate are preferred.

When it is desired to produce a reagent including a mixture of the sodium carbonate neutralized product and the heavy metal product derived therefrom, the amount of heavy metal salt added to the product resulting from the neutralization of thesulphonated castor oil with the alkali metal carbonate will depend upon the relative amount of heavy metal product, as a collecting or flocculating agent, desired in the final product. Accordingly, the amount of lead acetate which maybe added in the first example referred to-above may vary from a relatively small amount, such as lQO gmmadi tHe above parts are compu d 111 Pounds, 190 Suflicient o t t react particular pulp being treated i t being well und with and convert a large part of the alkali metal stood that e h bat'cli of material'ifimresent compound to the corresponding lead compound. itsWZ it respect t t amount f If the reagent is tobe used y for nothing, g/flo tion reagents which should be used to obtain heavy metal salt will be added thereto, while the optimum results. It is also'to be understood a collecting or flocculatingagent aloneisaiesired that subsequent to the mixing of the reagents the amount of hea metal salt added y be with the ore pulp, the actual step of separating sufficient @conyert all of the alkali metal product in to the correspondin heavy me 1 p duct. While either'the alkali metal'product prepared as described or the heavy metal product derived therefrom will give improved results in the concentration of ores, I usually prefer to use a mixture of the alkali metal and heavy metal products in order to obtain the benefits of the collecting and flocculating properties of the heavy metal product on slimed mineral, and increase the relurgical results and lowered total reagent costs are obtained. In froth flotation, it is only necessary to use about 30 to 40% of the amount of pine oil, cresylic acid or' other frother ordinarily used, and to add suflicient of the alkali metal product to produce the required volume of froth. In that way, greater selectivity control is. obtained as well as the more rapid and effective emulsification, andthe production of froth of facilities for mineral flotation.

In the concentration of minerals from their ores, the present reagents may be used in the form of the crude mixtures obtained in the manner described above or the sodium compound or the heavy metal compound or mixtures thereof, as the case may be, may be separated and used alone.

The amount of reagent which will be used will, in accordance with the usual practice, depend upon the particular ore being treated, the exact chemical and mineralogical nature thereof, the chemical character of the mill water and the temperature and physical characteristics of the type of flotation machine or even by tabling.

The advantages of the reagents of the present invention in the concentration of minerals will be better understood from the following examples of its'use, in all of which the reagent proportions are given on the basis of pounds per ton of dry material treated, and the assays of the goldbearing ores are given in gold value per ton of dry material.

metal salt added to the neutralized product and.

the present reagent along with some of the standsuch as pine oil or cresylic acid, improved metal-- smaller bubble structure which offers improved the mineral values may be effected in any desired Example I Old stamp mill tailings from the Chicagof district of southeastern Alaska assaying $3.10 in gold and consisting mainly of, auriferous pyrite,

free gold, and a small amount of amalgam, along with quartz and considerable quantities of sericite, calcite, chlorite and graphite were ground so that all of it passed through a 65 mesh screen and 68% passed through a 200 mesh screen. The

ground product was made into a pulp containing 22% solids and to it was added in a conditioning tank:

.1 Pounds The reagent as prepared above and containing the sodium and lead products-.." 0.4

Amyl xanthate 0,15 Pine oil 0.02 Starch 0.1

The starch was added as a depressant for the graphite, the amyl xanthate as an additional collecting agent, and the pine oil as a frothing agent.

The addition of reagents required one minute, after which agitation was continued for another minute.

chanical type, where it was agitated for eight minutes, during which time a rougher concentrate was floated .and collected. Upon removal of the tailings, the rougher concentrate was returned to the flotation machine where, without further addition of reagents, it was again treated for four minutes to float a finished concentrate. The tailings of this cleaning treatment constituted a middling which was returned for further treatment. The finished concentrate assayed $176.40, the middlings $5.07 and the tailings $0.44. With similar tests made with the same ore and under the same conditions, except that 0.03 lbs. of Aerofloat #31 was used instead of the reagent of the present invention, the concentrate assayed $141.10, the middlings $3.32 and the tailings $1.05. I

Example II The metallurgy of certain gold-bearing ores involves the recovery of elementary gold, galena, andvery small amounts of argentite and chalcopyrite, with the rejection of pyrite, pyrrhotite and graphite in the tailings. slime' flotation circuit in the treatment of such ores assaying $0.40 were made into various pulps containing from 12 to 30% solids (averaging about 20%) to which were added in a conditioning tank:

' Pounds The reagent as prepared above and containing both the sodium and heavy metal compounds 0.03 to 0.07 Amyl xanthate 0.006 to 0.012 60 Pine nil 0.03 to 0.07 Starch; 0.04

successfully use a relatively short period of treat- 70 ment of the conditioned pulp in the froth flotation machines.

The finished concentrate assayed on an average $300.00 and the tailings $0.15. The average 9 The pulp thus conditioned was transferred to a froth flotation machine of the me- The heads of the at which the operations were carried out. With As the action of the frother on the 35 reagent cost was $0.013. The recovery of lead in the slime size was high.

Example III The headsof the slime flotation circuit in the reatment of ores of the kind referred to in Example II were prepared and treated in a similar manner with the same reagents used in Example II, except that the reagent was the sodium product as prepared above, no heavy metal product being present. The finished concentrate assayed $300.00, and 'the tailings $0.17. The reagent cost was $0.015 per ton treated. The recovery of lead in the slime size was also high.

In tests on the heads of the slime flotation circuit in the treatment of ores of the kind referred to in Examples II and III but using standard reagent, the finished concentrate assayed $200.00 and the tailings $0.20 with a reagent cost of $0.035 per ton treated.

Example IV 200 mesh screen. The ground tailings were made into a pulp containing approximately 20% solids,

using one half sea water and one half fresh water. To the pulp thus prepared there was added in a conditioning tank:

. Pounds The reagent as prepared above and'contaming both the sodium and lead products 0.05 Amyl xanthate -I. 0.15

Cresylic acid 0.02 Reagent #637 0.02 Diesel oil 0.01

The Diesel oil was used to prevent an excessive amount of light unstable foam which otherwise would be produced when milling in sea water,

thereby enabling the use of the regular frothers.

The pulp thus conditioned was treated in a froth flotation machine in the manner set forth n the preceding examples toproduce a finished concentrate. The concentrate assayed $175.00, and the tailings $0.70. The values were in the form of exceedingly fine pyrite, a small amount of free gold, and amalgam.

In this example the reagents of this invention were found to havethe ability to form a stable froth, to fiocculate and assist in the recovery of minerals that could not be recovered with the standard reagents under the diflicult water, mineral surface conditions, and the 'low temperature standard reagents, the same ore gave concentrates which assayed from $105.00 to $140.00 while the tailings assayed from $1.20 to $1.50.

Example I In this example, ore from a small gold property in southeastern Alaska where flotation followed amalgamation, fine regrinding and tabling was ground, formed into a series of pulps and treated, in both fresh water and salt water, in

'the presence of the following reagents:

, Copper sulphate 0.12

The assays under salt water and fresh water conditions-were as follows:

With salt water circuit With fresh water circuit Heads Conc Tails Heads Cone. Tails 10.60 1 258.67 3.31 Averages 11.17 228.56 3.27

In a series of comparative tests made under similar conditions except that the lead product was not used as the collecting and flocculatlng agent, the assays were as follows:

With salt water circuit With fresh water circuit Heads Cone Tails Heads Cone. Tails 11.45 289. 70 4.77 Averages 10.23 187.61 3.88

Example VI In another test on gold-bearing ores the reagents used were as follows:

that used in Examples VI and VII was treated with the following reagents:

Iron product as prepared above- 0.08 Sodium product as prepared above 0.40 Pine il 0.04 Minerec B 0.003 Starch 0.04

The assays in this example were as follows:

Heads 0.44 Concentrates 298.20 Tails 0.17

Example IX In a test run on a high grade silver-lead ore from the Mayo district of Yukon Territory in which the silver carrying minerals present were tetrahedrite, proustite, argentite and galena, and which also contained zinc, pyrite cerussite and anglesite, a pulp of the ore was treated in the usual manner with the following reagents:

Pounds Sodium product as prepared above 0.50 Pine n 0.05 Amyhranfhatn (L12 Sodium car 0.30 sodium cyanide 0.40

The sodium carbonate and sodium cyanide were added to depress zinc and iron sulphide. The assays were as follows:

Heads $137.94 oz. ag.

Concentrates 1164.62 oz. ag- Tails 7.38 oz.ag.

The silver loss was due, to the presence of I anglesite and cerussite.

Pounds, The lead product as prepared above 0.08 The sodium product as prepared above 0.40 Pine oil- 0.04 Starch 0.04 The assays were as follo'wsf Heads- 0.44 Concentrates 249.90 Tails--- 0.17

In this example the test was of four hours duration. It is to be noted that the lead product of the invention was the only collecting and flocculating agent present.

Example VII In this example a gold-bearing ore was treated in the usual manner with the following reagents:

Pounds Zinc product as prepared above r 0.08- Sodium product as prepared above 0.40 Pine 00.. 0.04 Minerec B 0.003 Starch 0.04

'The Minerec B was used along with the zinc product of the invention as a collecting and flocculating agent. The assays were as follows:

Heads 0.44

Concentrates 256,30

Tai1s i 0.17 Example VIII In this example a gold-bearing ore similar to In a test made on an ore containing tungsten as well as copper, where the usual mill practice is to float copper and table flotation tailings for recovery of tungsten, the addition of a small amount of a mixture of the sodium and lead products of the invention caused the tungsten to be floated along with the copper.

From the foregoing it will be apparent that the product of the neutralization of sulphonated castor oil with an alkali or alkaline earth metal carbonate, and the corresponding heavy metal product, are particularly useful as frothing and collecting agents in the concentration of metals by the froth flotation method, and possess advantages in such a method over similar collecting agents prepared by saponifying the sulphonated castor oil with an alkali metal hydroxide such as sodium hydroxide.

In the accompanying claims, the term alkali carbonate is used as a generic term to include an alkali carbonate such as ammonium carbonate,

alkali metal carbonates and alkaline earth metal,

Pounds tralization of sulphonated castor oil with an alkali carbonate, and separating in an aqueous pulp the mineral values from the ore.

. 4. A process of beneficiating metalliferous ores which comprises admixing ground ore with a lead compound prepared by reaction of a lead salt with the product of the neutralization of sulphonated castor oil with sodium carbonate, and separating in an aqueous pulp the mineral values from the ore.

5. A process of beneflciating metalliferous ores which .comprises subjecting ground ore-to froth flotation in the presence of a reagent prepared by reacting sulphonated castor oil with at least 1.1 times its weight of an alkali metal carbonate, and separating in an aqueous pulp the mineral values from the ore.

6. A process of beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of a heavy metal compound prepared by reacting a salt of a heavy metal with the product of the neutralization of sulphonated castor oil with an alkali metal carbonate, and separating in an aqueous pulp the mineral values from the ore.

7. A process of beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of a lead compound prepared by reacting a lead salt with the product of the neutralization of sulphonated castor oil with an alkali metal carbonate.

8. A processof beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of the productresulting from the neutralization of sulphonated castor oil with an alkali carbonate and in the presence of a heavy metal compound formed by the reaction of a heavy metal salt with such neutralization product.

9. A process of beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of the product of the neutralization of sulphonated castor oil with an alkali metal carbonate and in the presence of a lead compound produced by reacting such a neutralization product with lead acetate.

10. A process of beneflciating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of a lead compound prepared by reacting a lead salt with the product of the neutralization of sulphonated castor oil with from 1.1 to 2 times its weight of an alkali metal carbonate.

11. A process of beneficiating metalliferous ores which comprises admixing ground ore with a reagent prepared by reacting a salt of a heavy metal with the product of the neutralization of sulphonated castor oil with sodium carbonate.

12. A process of beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of a lead compound prepared by reacting lead acetate with the product of the neutralization of sulphonated castor oil with sodium carbonate.

13. A process of beneficiating metalliferous ores which comprises subjecting ground ore to froth flotation in the presence of the product resulting from the neutralization of sulphonated castor oil with an alkali carbonate and in the presence of a lead compound prepared by reacting such a neutralization product with a lead salt.

HUGH w. COKE. 

